Decorators in Scale

# our class (can be anything..., think rendering, or stream processing)

class Coffee
    def cost
        1.50
    end
end

# our decorators

jack :milk do
    def cost
        super() + 0.30
    end
end
jack :vanilla do
    def cost
        super() + 0.15
    end
end

# the coffee

cup = Coffee.new.enrich(milk, vanilla, vanilla) # this list can....

# our tests

cup.cost.should == 2.10
cup.injectors.sym_list.should == [:milk, :vanilla, :vanilla]

# coffee is coffee

cup.should be_instance_of(Coffee)

For more info check out:
http://blog.jackbox.us/2015/09/decorators-in-scale.html